Which one of the following software packages is most suitable for professional desktop publishers?

Assuming you mean this

A. Broderbund Printshop

B. Corel Printhouse

C. Adobe PageMaker

D. Microsoft Windows

From a google search

It really comes down to preference. One that our marketing group uses is Quark, which is another one to add to your list. Out of those you listed, I'd recommend PageMaker, which can produce very professional results if you know what you're doing.